Hyundai Repair: Hyudai Matrix 2003, transmission problem, torque converter clutch, transmission shifts

Question
I get a small but noticeable vibration when my transmission shifts to overdrive, usually around 40-50 mph. It almost feels like running over the small bumps that the city puts out to divide lanes. shifting to overdrive is also a bit delayed, i have done 60000 KM service recently, fluids, belts, plugs and filters are all changed.
can you advise the reason for this problem.

Answer
This sounds like a torque converter clutch vibration.  Is there a possibility that the wrong fluid was installed in the transmission?  The primary reason Hyundai moved away from Dexron fluid was torque converter vibration.  I'm not sure of your transmission fluid specification because this is not a U.S. vehicle, but all U.S. Hyundais specify only SPIII transmission fluid.